UPDATE 12:40 EST:Reuters is now reporting that Ukrainian officials claim that the plane was shot down by pro-Russian rebels:

The Boeing 777 came down near the city of Donetsk, stronghold of pro-Russian rebels, interior ministry official Anton Gerashchenko said on Facebook, adding it was "shot down with a Buk anti-aircraft system by terrorists" - the term the Kiev government uses for militants seeking to unite eastern Ukraine with Russia.

Keep in mind: there has been no further confirmation on this, and Russian officials have denied any involvement or knowledge.

A Malaysia Airlines jet carrying nearly 300 people crashed near the border between Russia and Ukraine, according to Reuters and the Russian news agency Interfax. The airline company has confirmed that it has lost contact with the plane, a Boeing 777:

The flight was en route to Kuala Lumpur from Amsterdam, crossing over a highly volatile area at the time it went down. It was apparently still on the Ukrainian side, though the precise location remains unclear. Details are coming in very slowly.

According to the BBC, a spokesperson for the Ukrainian deputy interior minister claims that the plane was shot down by a missile, though there has been no confirmation on that.